致羔羊脑炎大肠杆菌的分离鉴定、耐药性及毒力基因检测

Isolation,identification,drug resistance and virulence gene detection of Escherichia coli causing lamb encephalitis

采用细菌常规分离和PCR等方法对分离株进行分离鉴定、药敏试验,并对相关耐药基因和毒力基因进行检测。结果显示,从病死羔羊脑组织和肺脏组织共分离鉴定3株致病性大肠杆菌,3株分离菌均呈多重耐药现象,其中对青霉素、阿莫西林、头孢他啶、头孢唑啉、头孢拉定、麦迪霉素、氟苯尼考、恩诺沙星、四环素、复方新诺明、替考拉宁表现出100%耐药,3株菌均对美罗培南、亚胺培南表现出高度敏感;A1、A2分离株同时对多西环素、多黏菌素B中度敏感,对美罗培南、亚胺培南表现出高度敏感。A1、A2、A3分离株共检测出gyrA、sul3、blaTEM、blaCTX-M、aadA1、aph(3′)-Ia等6种耐药基因和fimH、crl、hlyE、pta、mota、luxs、csgA、pap、wcaM等9种毒力基因;动物试验结果显示,小鼠感染后,存在不同时间段死亡现象,剖检发现小鼠内脏出现不同程度病变,且从死亡小鼠肺脏和脑组织中均分离到接种细菌。结果表明,新疆石河子某规模化羊养殖场因神经系统感染死亡的细菌性病原是大肠杆菌;从肺脏和脑中共分离出3株致病性大肠杆菌,并且其存在多重耐药以及携带较多耐药基因和毒力基因并导致小鼠的发病死亡。

The bacteria were isolated and identified by routine bacterial isolation and PCR,and the drug sensitivity test was carried out,and the related drug resistance genes and virulence genes were detected.The results showed that three strains of pathogenic Escherichia coli(E.coli)were isolated and identified from the brain and lung tissues of dead lambs,and all three strains showed multi-drug resistance,they all showed 10o%resistance to penicillin,amoxicillin,ceftazidime,cefazolin,cefradine,midecamycin,florfenicol,enrofloxacin,tetracycline,cotrimoxazole and teicoplanin.All three strains were highly sensitive to meropenem and imipenem.Al and A2 isolates were moderately sensitive to doxycycline and polymyxin B,and highly sensitive to meropenem and imipenem.A total of 6 drug resistance genes such as gyrA,sul3,blaTEM,blaCTX-M,aadA1 and aph(3')-Ia and 9 virulence genes such as fimH,crl,hlyE,pta,mota,lurs,csgA,pap and wcaM were detected in Al,A2 and A3 isolates.The results of animal experiments showed that the mice died at different time periods after infection.The autopsy showed that the organs of the mice had different degrees of lesions,and the inoculated bacteria were isolated from the lungs and brain tissues of the dead mice.The results showed that the bacterial pathogen of death due to nervous system infection in a large-scale sheep farm in Shihezi,Xinjiang was E.coli.A total of 3 strains of pathogenic E.coli were isolated from the lungs and brains,and they had multiple drug resistance and carried more drug resistance genes and virulence genes,leading to the morbidity and mortality of mice.